The first examples of the directed, boron-mediated aldol reaction between different ketones are presented. Transformation of a variety of ketones to their corresponding boron enolates with Chx2BCl/Et3N, followed by reaction with acceptor ketones in diethyl ether, and oxidation of the resultant boron aldolate (H2O2, MeOH/pH 7 buffer), provided the aldol addition products. The reaction was most f...

The dynamic exchange of enamines from secondary amines and enolizable aldehydes has been demonstrated in organic solvents. The enamine exchange with amines was efficiently catalyzed by Bi(OTf)3 and Sc(OTf)3 (2 mol %) and the equilibria (60 mm) could be attained within hours at room temperature. The formed dynamic covalent systems displayed high stabilities in basic environment with <2 % by-prod...

backgrounds: subclinical ketosis can cause greater economic loss due to a lack of clinical symptoms. objectives: the present study was aimed to design a chemical method for measuring serum ketone bodies in the affected subclinical cows. methods: acetoacetate concentrations were measured using a nitroprusside reaction and b-hydroxy butyric acid (bhba) which was oxidized to acetoacetate using nan...

One series of half-analogues of Michler’s ketone containing one or more terminal methoxysubstituents with variable tertiary amino groups have been used in this study. NMR spectralresults for the parent ketones confirm earlier findings that ortho proton shifts are apparentlyindependent from steric effects in derivatives of Michler’s ketone because the ring current andcarbonyl-induced shifts are ...

In this study, NRTL and UNIQUAC thermodynamic models were used to predict the composition of ternary mixtures of solvents+ m/o/p-cresol+ water in organic and aqueous phases. Various solvents are used for the separation of cresols from water. In this study, methyl propyl ketone, methyl isopropyl ketone, methyl butyl ketone, and methyl isobutyl ketone solvents were investigated. Intermolecular in...

Mechanistic studies of the enolization of 2-methylcyclohexanone mediated by lithium hexamethyldisilazide (LiHMDS; TMS2NLi) in toluene and toluene/triethylamine (Et3N) mixtures are described. Structural studies of LiHMDS/ketone mixtures in toluene reveal cyclic dimer (TMS2NLi)2(ketone). Rate studies using in situ IR spectroscopy show the enolization proceeds via a dimer-based transition structur...